-If you own a trailer, the first accessory you want to invest in is a quality trailer hitch lock. Unfortunately, trailers are often sought out by thieves since they’re relatively straightforward to steal and easy to sell once stolen. In addition, stolen trailers have a low rate of being recovered. Even if they are found, there’s a good chance all the stuff stored inside is gone. A trailer lock is a small investment that could potentially save you a lot of headaches and heartache down the road. After all, the money spent on a trailer lock will be less than the cost of replacing a whole trailer.

There are several different types of trailer hitch locks available, and in this article, we’ll take a look at the most popular, bestselling, and cost-efficient products. We’ll also go into detail about why you need a trailer lock, what to look for when shopping for one, and how to choose the right one for your needs.

For more information on the best trailer hitch locks, refer to our table of contents.

Promoted Product: Altor SAF Trailer Lock

Altor SAF Trailer Hitch Lock

Photo credit: Manufacturer.

A trailer hitch lock isn’t much good if the bad guys can easily cut their way through it, so the folks at Altor Locks designed the SAF trailer lock to be resistant to power tools that can cut away less robust locks. This was achieved thanks to Altor’s geometry, which can keep angle grinder blades up to five inches at bay. Compared to other locks that couldn’t survive even two minutes of angle grinder attacks, Altor boasts its SAF held off an angle grinder attack for more than an hour!

Made of hardened cast steel for increased hardness, the SAF can take on repeated attacks. It even boasts an anti-drill design that can fight off attacks to its internal lock and mechanism. And for more sophisticated thieves, its disc detainer lock is extremely pick-resistant.

The Altor SAF is available in two sizes to fit most 2-inch and 2 5/16-inch A-frame and channel mount couplers.

2. Runner-Up: Trimax UMAX100 Premium Universal Solid Hardened Steel Trailer Lock

trimax umax100 premium universal trailer lock

It may seem trivial, but this model's keyhole cover is a smart feature as it keeps road grime out of the lock. Photo credit: Amazon.com.

An even heavier-duty trailer lock is Trimax’s UMAX100 universal coupler lock. Like the UMAX50, the UMAX100 trailer hitch lock features a 9/16-inch shackle and offers 360 degrees of solid hardened steel with a patented dual-purpose coupler lock. Designed to fit most couplers from 1-7/8 to 2-5/16 inches, the UMAX100 takes protection to a new level with a ballistic-grade nylon housing that can absorb hammer blows while also giving it protection against harsh weather conditions.

The nylon housing also incorporates a keyhole cover to keep out dirt and grime. This coupler lock features a type A key, which is a spring-loaded, seven-pin high-security key. This helps resists attempted drill outs.

Trimax offers a lifetime warranty on all their products and is an Amazon’s Choice with over 2,000 very positive reviews.

3. Master Lock Receiver Lock (2866DATSC)

master lock swivel head receiver lock

Designed for vehicles, trailers, and RV hitch locks, this Master Lock receiver lock fits 1/2-inch and 5/8-inch receivers. The 1/2-inch pin is rated for Class I/II 3,500-pound load, while the 5/8-inch pin is good for Class III/IV 10,000-pound load. The usable length of the receiver pin is 2.75 inches.

The receiver lock features a convenient push-to-lock mechanism; simply push the lock body onto the pin and remove the key. It has a durable design with a weather-resistant seal and watertight cap, which helps protect the lock from moisture and dirt. The four-pin cylinder prevents lock picking, while the keyway is constructed with brass to make it resistant to corrosion.

There is also a patented, stainless steel swivel head that rotates 360 degrees for easy access. This is a padlock-style hitch lock that is used in place of the standard pin and clip to prevent theft. It comes with 1/2- and 5/8-inch pins, two keys, and the locking swivel head.

4. Trimax Premium Key Receiver Lock (T-3BLACK)

trimax t-3black premium key receiver lock

Trimax keeps the weather out with O-rings and a keyhole cap. Photo credit: amazon.com.

Manufactured from high quality, forged hardened steel is Trimax’s premium key receiver lock. This product features a rugged black epoxy powdercoat and comes with an O-ring seal and watertight cap to help keep out dirt and corrosion. Trimax says the lock cannot “pop” open, nor can it be false locked. It’s easy to use, requiring just a quarter turn to lock and unlock the head.

The 5/8-inch pin fits all Class III, IV, and V receiver hitches and fits up to a 2.75-inch span. This is a type A key, which makes it a spring-loaded, seven-pin high-security key. It is resistant to attempted drill-outs and will not bend or break. The Trimax trailer hitch lock comes in at 1.2 x 5.8 x 8.8 inches.

5. Reese Towpower Universal Coupler Lock (72783)

Universal trailer hitch lock

With its bright-yellow finish the Reese coupler lock tells potential thieves to look elsewhere. Photo credit: Amazon.com.

This premium lock comes from Reese Towpower and is a universal coupler lock measuring 9 x 9 x 3 inches. It’s manufactured with an aluminum body and heavy-duty steel lock bar, designed to be a universal fit with a ratchet design with 11 locking positions. It can be used on 1-7/8-, 2-, and 2-5/16-inch couplers. The durable bright yellow finish acts as a theft deterrent, while the premium lock resists picking, prying, and drill outs.

If you have never heard of the Reese brand, the company was originally founded in 1952 and is a household name in the heavy-duty towing industry, as well as a market leader in automotive and recreational product solutions. Reese’s Towpower hitch lock is a good way to guard against trailer tow-away theft.

6. Cocoweb C-Lock Heavy Duty Locking Hitch Pin

cocoweb c-lock heavy duty locking hitch pin

Cocoweb’s C-Lock heavy-duty hitch pin lock comes in 1/2- and 5/8-inch sizing. The 1/2- and 5/8-inch pins are available in silver, while the 5/8-inch pin features a black finish. This locking hitch pin has a standard design, featuring a weatherproof cap that protects the keyhole by keeping out water and grime as well as keeping the lock free of rust. No drilling or mounting is required to use this locking hitch pin, simply slide it in, lock it, and you’re ready to go.

The pin fits Class I, II, III, and IV hitches with a max outer width of 2.75 inches and comes with two unique laser-cut keys. Cocoweb suggests verifying the dimensions of your hitch, as these locking pins do not fit all vehicle models.

The solid steel lock is a total of six inches long and has a barbell locking mechanism designed to make the lock fit more snugly and securely. Cocoweb offers a one-year warranty on its hitch pin lock.

7. Trimax UMAX50 Premium Die-Cast Dual Purpose Coupler Lock

trimax umax50 universal die cast dual purpose coupler lock

We like Trimax's durable hammertone finish. Photo credit: Amazon.com.

Designed as a “one size fits all,” Trimax offers a premium die-cast coupler lock with a dual ratchet lock system. The exclusive design provides 360 degrees of hardened steel protection with a rust-proof hammertone epoxy finish. The UMAX50 can be used with 1-7/8-, 2-, and 2-5/15-inch couplers and features a keyhole cover that slides up to keep out dirt and grime.

Trimax’s UMAX50 trailer lock uses a Type A seven-pin spring-loaded high-security key which resists attempted drill outs. Trimax also paid special attention and designed an extra strong key that they say will not bend or break. The shackle is made from 16mm hardened steel with six large ratchet teeth that won’t pull out.

This product costs a bit more than some of the competition, but it comes with a full lifetime guarantee.

8. Master Lock Trailer Lock

master lock trailer hitch lock

This Masterlock design is resistant to bolt cutters. Photo credit: Amazon.com.

This trailer lock from Master Lock is designed to fit most trailer couplers, ranging from 1 7/8 inch to 2 5/16 inch. It features an advanced corrosion-resistant zinc mechanism and two keys that provides resistance to picking and prying and comes with a limited lifetime warranty for peace of mind. This product is “keyed alike,” which means they all use the same key. So if a thief has access to the key, there’s a good chance they’ll be able to easily unlock this trailer lock. The benefit to “keyed alike” products is that one key will unlock all your Master Lock locks, but it’s a strange price to pay for convenience.

This trailer lock is a solid, heavy-duty product that is well-built and durable. So long as a potential thief doesn’t have access to a key, it’s one of the toughest locks to break off.

9. Proven Industries Trailer Hitch Lock

Trailer hitch lock

The Proven trailer hitch lock is a superb piece of kit—at a price. Photo credit: Amazon.com.

Proven’s locks aren’t for everyone. The #2516 is a 10-pound, ‎8.15 x 7.76 x 7.6-inch slab of solid steel made in the USA by a family-owned and -run company. They offer multiple models in 2- and 2-5/16-hitch sizes, as well as specialty locks for things like Jayco trailers and Titan hitches.

As some of the most highly rated trailer hitch locks on the market, Proven gives you both cut and picking protection lacking in less expensive models, as well as securing your safety chains. But expensive is the keyword, as Proven trailer locks play in the same price bracket as the Amplock. However, if you’re leaving an expensive trailer with valuable cargo somewhere, it makes sense to spend a little more to protect it. 

10. Tow Ready GorillaGuard Coupler Lock

Heavy duty hitch lock

The Gorilla coupler lock installs without tools. Photo credit: Amazon.com.

For a more affordable option, take a look at the Tow Ready GorillaGuard coupler. This product is designed to shield the lock from tampering devices and fits most two-inch couplers. According to the company, this coupler will only work on coupler widths (including lip) with a diameter of 3-13/16 inches or smaller, while the height of the coupler lip cannot exceed 5/16 inches.

This is a surround lock that is keyed uniquely, which means you don’t have to worry about a thief potentially having the same key. It is designed to protect unattended trailers, but it is also tow-ready and installs easily without tools.

The Tow Ready GorillaGuard comes with two keys and a one-year limited warranty.

What is a Hitch or Trailer Lock?

As their name suggests, a hitch or trailer lock is designed to keep your trailer from getting stolen. A hitch lock is a product that keeps your trailer hitch and receiver together, with the lock preventing someone from lifting the receiver. This ensures that a thief isn’t able to unhitch the trailer unless the lock is off.

A trailer lock, also known as a coupler lock, keeps your trailer safe when it’s unhitched from your vehicle. Without a coupler lock, someone can simply drive up to your trailer, hitch it, and drive off. These locks fit over the coupler on the trailer’s tongue, preventing someone from hooking up their vehicle and driving off.

Essentially, a hitch or trailer lock plays the role of an insurance policy. Without one of these locks, a savvy thief can drive off with your trailer in a matter of minutes, if not seconds. Unfortunately there is no such thing as a lock that will completely prevent a thief from stealing your property if they want it badly enough and have the time to break off the lock. But locks do serve as a deterrent and some may cause enough of a struggle that the thief gives up.

How Do I Keep My Trailer from Being Stolen?

A trailer hitch lock is your first line of defense against an unattended trailer being stolen. Without one, a thief can literally back a truck up to it and drive off, and that happens all the time. It’s the sort of crime that happens in broad daylight. Adding even a simple hitch lock means someone is now going to have to use tools and make noise to get to your trailer, which is enough to make people drive on to the next target.

But there’s one big weakness that even an indestructible AMPLOCK or Proven hitch lock can’t overcome: The coupler itself. On many trailers, especially smaller ones, the coupler that attaches the trailer to the tow vehicle’s ball hitch is held on with a few bolts. As you can pick up a cheap replacement for about $20, it’s possible to unbolt the hitch ball coupler from the trailer straight tongue, bolt on a new one, and drive off leaving your nice lock coupler on the ground. One option is to tack weld your bolts on. That’s secure, but you’ll have to grind off the welds if you ever need to replace the coupler. An easier option is to add a trailer chock lock to one of the trailer wheels. Now, there’s another layer of protection that will need different tools to remove, taking more time and making more noise.

Of course, you could always just take your own trailer wheels and tires with you. It’ll take a few minutes to jack it up, put it on blocks and take your wheels and tires with you, but it’s very hard to steal a trailer without tires. And if you’re storing it for a long time, it’s also much easier on your tires—they’ll be much less likely to be flatspotted or rotted.

What to Look for When Shopping for a Hitch or Trailer Lock

Before you start shopping, you’ll need to determine your hitch class if you’re shopping for a hitch lock. Hitches range from Class I to Class V, and not all hitch locks will support up to Class V hitches. Generally, most trailer locks are either 1/2- or 5/8-inch pins and you’ll need to make sure the lock works with your hitch before purchasing. Generally, Class II hitches use 1/2-inch pins, while Class III to Class V hitches use 5/8-inch pins.

When shopping for a hitch or trailer lock, you’ll want to pay close attention to the material it’s constructed from. You will ideally want to purchase a product made from high quality steel, or even hardened steel. Softer metals like aluminum may be lightweight, but they’re easy to damage, allowing a thief to simply take a hammer to your lock.

The next important factor is seeing whether the lock uses a unique key, or if the key design is shared across an entire product’s lineup. Naturally you will want a product that is uniquely keyed, so you don’t have to worry about a thief potentially having a key to your lock.

Depending on where you live and your weather conditions, make sure you invest into a lock that can withstand harsh weather conditions. Some products will corrode and rust quicker than others, potentially causing the lock to seize up. Check user reviews if you live in an area that sees snow or rain, as a rusted keyhole will cause you many headaches. At the very least, make sure you purchase a product that has a weatherproof cap for the keyhole.

If you’re purchasing a trailer or coupler lock, make sure it fits your exact application. Although many products are advertised as being universal, some may not work with certain trailers or hitches. Check user reviews or contact the manufacturer to confirm a particular product works with your specific application.


Recent Updates

December 9, 2022: Updated product links. 

October 11, 2021: Updated specifications, removed unavailable Connor locks, added Proven Industries lock. Added FAQ section.

August 24, 2021: Added a new promoted product recommendation.

January 26, 2021: Updated with a promoted product recommendation.

We are committed to finding, researching, and recommending the best products. We earn commissions from purchases you make using the retail links in our product reviews. Learn more about how this works.

Photo credit: Ford Motor Company